Cylinder head construction, bridge cooling



' Oct. 12, 1948. a R. 1-}. SHEPPARD 2,450,99

CYLINDER HEAD CONSTRUCTION, BRIDGE COOLING Filed May 5, 1947 I 2 Sheets-Sheet 1 Oct. 12, 1948. SHEPPARD 2,450,998

CYLINDER HEAD CONSTRUCTION, BRIDGE COOLING Filed May 5, 1947 2 Sheets-Shae; 2

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y /f W i /fi I? 7/ 22 7:27- g I N v v I EW/l/l/l/l/l/l/M i; /f w u Patented Oct. 12, 1948 Application May 5, 1947 This invention relates to amethod of cooling the bridge of metal between the valve seat inserts .b'f an internal combustion engine and has for its particular object the provisions er means to reduce the thermal stress in this member and thereby eliminate undue distortion of this bridge. In .so doing We greatly increase the length of life of the exhaust valve seat insert and entirely avoid the fractures between the inserts which occurred in cylinder heads used without drilling the new passages.

A further object of the invention is to equalize the temperature in the bridge between the two valve seats to lessen the distortion of the valve seat inserts, to prevent the inserts from coming loose and for greatly increasing the length of time necessary between the valve grinds.

In the drawings:

Figure 1 is a plan view of a cylinder head embodying the invention.

Figure 2 is a section taken through the common axis of the injector and combustion chamber and passing centrally between the valves stem guides.

Figure 3 is a section through the axes of the valve guides.

Figure 4 is a side view of the cylinder head.

Figure 5 is a section on line 5-5 of Figure 1.

Figure 6 is a section on line 6-6 of Figure 2.

The cylinder head In shown in Figure 1 has a recess II to receive the injector, a recess l2 directly below this to receive the combustion chamber and nearby has recesses l4 and i5 receiving respectively the inlet and exhaust valve stems.

As best seen in Figure 3, there is a water space l6 between the valve guides and the conventional communicating water spaces I l and I 8 on both sides. The metal bridge 20 extends down to the lower face of the cylinder head I!) between the inlet valve recess 2| and the exhaust valve recess 22. This bridge 20 carries away the heat from this particular portion of the cylinder head which obviously is the hottest part of this casting.

It has been considered impossible to cool this bridge 20 as a vertical bore would weaken the bridge to too great an extent and there is extreme difliculty in conveying cooling water through the bridge in any other manner. This difficulty however has been overcome as shown in Figure l by boring a hole from the far side of the casting as seen in Figure 1 at point 25; the hole, which is numbered 26, extending to a point in the bridge well to the front (as seen in Figure 1) of the plane passingthrough the axes of the two valve guides l5 and I6. At an intermediate point, such as 21, the passageway or bore 26 communicates 6 Claims. (01.52pm) "directly downward with "erial m. via-p10 Z the engine block, meeting 'a'watei' opening-in the latter, not shown.

"At'theeh'd of the bore 26, which is very close to the center line of the engine cylinder indicated by the dot and dash line '29, the top of the cylinder-'h'ead is bored as at 30 leading thru the short thickness of inet'a-l 3| to the cooling water space 32. Through this hole 30, later closed by aplug', the'vertic'al bore 34 is drilled through the instal bridged!) forming a continuation of the walls 35 and 36 and this vertical bore 34 meets the horizontal bore 26 as best seen in Figure 2. We thus have a free passage of cooling water which rises through the bore 34 into the space 32 and constantly drawing cooler water through the passage 21 from the engine casting below and not shown.

The only change that need be made in the cylinder head casting in order to provide the cooling passageways in the bridge is a mere ridge 40 from the bridge 20 to the wall 4 I. This ridge need only be a half-inch wide and a bit over a quarter of an inch high to give sufiicient metal to permit the bore 26 being a half inch above the bottom face 44 of the casting.

Having described my invention, what I claim is:

1. A cylinder head casting having therein a recess for receiving an injector, a, plurality of recesses in proximity to the injector recess and serving as guides for valve stems in which a bridge of metal extends between the valve guide recesses and the bottom of the casting, characterized by a passage through the bridge parallel to the lower face of the casting and a communicating passageway located between the valve recesses and parallel to the axis of the injector opening.

2. A cylinder head casting for a Diesel engine having therein coaxial recesses to receive an injeetor and a combustion chamber insert, and having in proximity thereto an inlet valve guide and an exhaust valve guide, recesses in the bottom of said casting, coaxial with said guides for reception of valve seat inserts, a bridge of metal extending downwardly from the guides to the bottom of the casting forming a bridge integral with and proximate to the combustion chamber recess characterized by the provision of a vertical bore extending downwardly through the bridge, in proximity to the combustion chamber recess, and a bore at right angles thereto and communicating therewith, extending horizontally to said vertical bore and between the axes of said valve.

insert recesses. i

3. The device of claim 2 in which a ridge rises from the bottom wall of the cylinder head, immediately above the horizontal bore. 7

4. A water-cooled cylinder head for a Diesel engine of the type having an exhaust passageway through the cylinder head .in a generally horizontal direction and having about a vertical axis a recess for the exhaust valve stem, and a recess for an exhaust. valve insert characterized by a horizontal bore extending within a half-inch of the exhaust valve insert recess and communicating with a vertical bore leading from the water chamber down to said horizontal bore, said horizontal bore having a communicating passageway leading through the bottom face of the casting.

5. A water-cooled cylinder head casting having integral with its bottom wall a bridge extending between the ends of the inlet and exhaust passageways and having in its lower face a cylindrical recess to receive a combustion chamber in proximity to said ends, a horizontal water passageway extending between said ends and having communicating bores extending vertically, one bore leading from one end of said horizontal passageway upwardly to the water chamber and the other extending downwardly through the bottom face of the cylinder head, said vertical bores lying on opposite sides of a vertical plane through said ends.

6. A Diesel engine cylinder head of the type having therethrough an inlet passage, an exhaust 4 passage, chambers for cooling water, guides for the inlet and exhaust valves and recesses for valve inserts, in which a bridge of metal extends from said guides down to the bottom surface of the cylinder head between the valve insert recesses: characterized by the provision of a cooling bore extending horizontally in the bridge in a line perpendicular to the plane containing the axes of the valve guides, said bore having vertical communicating bores, one communicating with the water chamber above the valve insert recesses and the other extending through the bottom of the cylinder head for communication with the water system of the engine block.

RICHARD H. SHEPPARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,298,213 Jardine Oct. 6, 1942 2,339,972 Anderson Jan. 25, 1944 FOREIGN PATENTS Number Country Date 93,827 Austria 1923 801,487 France 1936 

